May was 1.5°C warmer than the monthly average for the last 30 years. The Meteorological Office said the temperature reached a maximum 7°C above the norm, while the humidity remained relatively low.
May 26 was the warmest day, when the mercury hit 32.2°C.
The average sea surface temperature was also 1.6°C warmer than the monthly average. April, on the other hand, had been colder than average, averaging 15.3°C.